Process of treating wood separators for storage batteries.



Y NITED STATES PATENT OFFICE.

JAMES M. SKINNER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO PHILADEL- PHIA STORAGE BATTERY COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A COR-- PORATION OF PENNSYLVANIA.

rnocnss orTREATIfie wool) SEPARATORS FOR STORAGE BATTERIES.

No Drawing.

To all whom it may concern Be it known that I, JAMES M. SKINNER, of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Processes of Treating 'Wood Separators for Storage Batteries,

whereof the following is a specification.

It is the object of my invention to proacid, and subjected to the action of the battery, and form acetic acid or other products which are deleterious to the battery. Such deleteriousconstituents of the natural wood are principally contained in its lignone; the formation of acetic acid and other acids of like nature being a characteristic of such decomposition of lignone. For instance, acetic acid may be formed from the wood by simple hydrolysis of lignncellulose, and oxidation of wood nuclei of ketonic or aldehydic structure. It is characteristic of my invention that the wood is deprived of said deleterious constituents by salts, and that the wood treated therewith may be allowed to dry in the interim between its treatment and its inclusion in a battery, without materially shrinking, warping, or cracking. Moreover, my invention is advantageous in that separators treated in accordance therewith have greater strength and durability than wood separators treated with the ordinary acid or alkaline processesl The wood to be treatedis cut in suit-able forms, approximately plane'sheets, and immersed in an aqueous solution of salt; preferably neutral sulfite or bisulfite. For instance, I have used an aqueous solution of sodium bisulfite (Na-HSO containing 25 per cent, by weight, of that salt; being a solution which is nearly saturated. However, it isto be understoodthat other similar salts may be employed, and, that the percentage of salt in the solution may be less; for instance, a solution containing 7 per cent. of such salt may be employed, although, of course, necessitating a longer time of treatment of the wood than would be required in the employment of stronger Specification of Letters Patent.

Application filed March 13, 1912. V Serial No. 683,631.

Patented Feb. 11,1913.

solutions. Although such solutions may be used at atmospheric temperatures, and open to the atmosphere; higher temperatures and corresponding pressures tend to accelerate the desired reactions and prevent reverse action, e. condensation of the products.

1 For instance, a temperature of from 100 to 175 degrees centigrade, with corresponding pressure, may be advantageously employed.

The treatment with neutral sulfites involves a simple hydrol tic action. In the presence of the lignocel ulose complex, undergoing decomposition, the sulfite is dissociated, the base going to saturate acid groups, and the sulfite ions (SO H) going to aldehydic and ketonic groups; both products being readily soluble in water, and therefore susceptible of being washed out o f'the treated wood. With bisulfites, the hydrolizing action is greater than with neutral sulfites. Moreover, the base serves to from the region of action, and the process is aided by sulfonation of GH:OH groups and the addition of SO,H to aldehydic and ketonic groups, while the presence of the excess of bisulfite, by virtue of its deoxidiz .being washed out of the treated wood.

The Wood separators. treated as above contemplated may be washed, to free them of said products which are soluble in water, and then dried with or without artificial heat, and with or without pressure. Good results are obtained by laying the'separators horizontally in piles, with a weight on top of'each pile.

I do not desire to limit myself to the particular salts named or to the precise pro; portions thereof above stated, or to the par ticular temperatures named, as various modifications may be made therein without departing from the essential features of my invention as defined in the appended claims.

I claim 1. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of neutral sodium bisulfite while maintaining said solution at a temperature of from 100 to 175 degrees centigrade; washing from the treated wood the products of decomposaturate acid groups and to remove them I sition effected, by the action of said solution; and, drying the wood, under pressure.

Copies 01 this patent may be obtained for 2. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a'salt of sulfur-one acid while maintaining said solution at a temperature of from 100 to 175 degrees centigrade; washing from v the treated wood the products of decomposition effected by the action. of said solution;

and, drying the wood, under pressure.

3. The process of treating'wood separa tors for storage batteries which consists in immerslng them in an aqueous solution of a salt of sulfurous acid, washing from the treated Wood the products of decomposition effected by the action of said solution; and,

drying the wood, under pressure.

4. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of sulfurous acid; and, washing from ,the treated wood the products of decomposition effected by the action of saidsolution. in

In testimony whereof, I have hereunto:

signed my name at Philadelphia, Pennsylfive cents each, by addressing the Commissioner of "Patents, 'Washington,D. G. a

11th (eleventh) day of March 

